“Draindown system" means an active solar energy system in which the fluid in the solar collector is drained from the solar energy system under prescribed circumstances.
“Dwelling" means any building which contains one or 2 dwelling units.
“Flammable liquid" means a liquid having a flash point below 100ºF and having a vapor pressure not exceeding 40 psia at 100ºF.
“Heat exchanger" means a device designed to transfer heat between two physically separated fluids.
“Heat transfer fluid" means the medium used to transfer energy from the solar collectors to the thermal storage or load.
“Heated space" means any space maintained at a temperature of at least 50ºF.
“Hot water" means water heated for domestic or industrial use.
“Liquid system" means an active solar energy system that uses liquid as the heat transfer fluid.
“Maximum operating pressure" means the maximum pressure experienced in a system, under any normal operating conditions including no-flow.
“Maximum operating temperature" means the maximum temperature experienced in a system, under any normal operating conditions including no-flow.
“No-flow condition" means the condition that results when the heat transfer fluid does not flow through the collector array due to normal shut-down or malfunction.
“Open loop system" means an active solar energy system in which water for domestic or industrial use is directly heated in collectors.
“Outgassing" means the emission of gases by component materials usually during exposure to elevated temperatures or reduced pressures.
“Owner" means any person having a legal or equitable interest in the solar energy system.
“Photovoltaic" means a solar energy system that converts radiant solar energy directly into electrical energy.
Free from impurities present in amounts sufficient to cause disease or harmful physiological effects and conforming in its bacteriological and chemical quality to the requirements specified in ch. NR 809
“Primary solar duct system" means the duct system between the collectors and thermal storage and the ducts making connection to the space distribution system.
“Seal of quality" means a written approval by the department documenting certification and compliance with specific quality standards.
“Solar energy system" means equipment which directly converts and then transfers or stores solar energy into usable forms of thermal or electrical energy.
“System designer" means a person who offers for sale a solar energy system as a complete package, the components of which may be produced by different manufacturers.
“Thermal resistance (R)" means a measure of the ability to retard the flow of heat.
SPS 371.10 Note
Note: The R-value is the reciprocal of the heat transfer coefficient, expressed by U (R = 1/U). The higher the R-value of a material, the more difficult is it for heat to flow through the material.
“Thermal storage" means a container and its contents used for storing thermal energy.
“Tilt angle" means the angle above horizontal of a plane surface.
“Toxic fluids" means fluids which are poisonous or irritating in nature or composition.
SPS 371.10 History
Cr. Register, June, 1986, No. 366
, eff. 7-1-86; correction in (31) (b) made under s. 13.93 (2m) (b) 7., Stats., Register, August, 1995, No. 476
; correction in (11) made under s. 13.92 (4) (b) 6., Stats., Register December 2011 No. 672
SPS 371.20 Purpose.
Pursuant to s. 101.175 (4) (c)
, Stats., this subchapter establishes quality standards for materials and workmanship for solar energy systems and components. Sections SPS 371.21
shall apply to active solar energy systems and components. Section SPS 371.30
shall apply to photovoltaic solar energy systems and components.
SPS 371.20 Note
The requirements of this subchapter are recommended standards. See s. SPS 371.03
SPS 371.20 History
Cr. Register, June, 1986, No. 366
, eff. 7-1-86; correction made under s. 13.92 (4) (b) 7.
, Stats., Register December 2011 No. 672
SPS 371.21 General installation requirements. SPS 371.21(1)(a)(a) Access.
Components shall be accessible for required routine maintenance without trespassing on adjoining property or disassembling any major portion of the solar energy system, building or dwelling.
Components within 10 feet horizontally of a chimney or vent shall be at least 2 feet below the top of the chimney or vent.
The location of components may not interfere with the operation of required doors, windows or other building components.
SPS 371.21 Note
Note: Components may be subject to local zoning requirements.
Combustible materials may not be exposed to components having maximum operating temperatures that can cause ignition. Clearances to combustible materials specified in the component listing or by the component manufacturer shall be maintained.
Clearance between combustible materials and unlisted components shall be maintained in accordance with Table 371.21-A.
Clearance Between Combustible Materials and
- See PDF for table
1If approved insulation protects the component, the required clearance may be reduced by 50%.
(2) Material tests and standards.
The installation of, as well as all materials used in the construction of, solar energy systems shall meet the applicable requirements specified in chs. SPS 320
, and 381
and this chapter. Where different chapters specify different requirements, the most restrictive material test and installation standard shall apply.
SPS 371.21(3)(a)(a) General.
Insulation of piping, ducts and thermal storage containers shall be of a type satisfactory for its intended purpose and installed in accordance with recognized standards and practices.
1. `Flame spread rating.'
The flame spread rating for all insulation materials may not exceed the following values:
Plastic foam: 75
Other insulation materials: 150
2. `Compressive loads.'
Insulation shall be protected against compressive loads from pipe and duct supports and storage tanks.
3. `Exterior insulation.'
Exterior insulation shall be capable of withstanding moisture, ultraviolet radiation, and environmental exposure.
Pipes of nominal size of one and one-half inch or larger shall be insulated to a thermal resistance value of R-4 or greater. All other piping in the solar energy system shall be insulated to a thermal resistance value of R-3 or greater. A vapor barrier, if installed, shall be located on the warm side of the insulation.
Ductwork located in unheated spaces shall be insulated to a thermal resistance value of R-11 or greater, where space permits. Ductwork in heated spaces shall be insulated to a thermal resistance value of R-3 or greater. A vapor barrier, if installed, shall be located on the warm side of the insulation.
SPS 371.21(3)(d)1.1. `Thermal storage - liquid systems.'
Thermal storage for liquid systems located in unheated spaces shall be insulated to an overall thermal resistance value of R-16 or greater. Thermal storage for liquid systems installed in heated spaces shall be insulated to an overall thermal resistance value of R-11 or greater.
2. `Thermal storage - air systems.'
Thermal storage for air systems located in unheated spaces shall be insulated to an overall thermal resistance value of R-38 or greater. Thermal storage for air systems installed in heated spaces shall be insulated to an overall thermal resistance value of R-11 or greater.
SPS 371.21(4)(a)(a) Protection against vermin.
All penetrations of the building or dwelling by components shall be properly sealed with noncombustible material to prevent the entrance of vermin.
(b) Protection against vehicular or pedestrian traffic.
Components exposed to vehicular or pedestrian traffic shall be protected against impact damage.
(c) Protection against water penetration.
All penetrations by components into a building or dwelling from the outside shall be properly sealed and waterproofed with approved materials to prevent leaks, insects and drafts from entering the building or dwelling. All penetrations shall be made using weatherproof devices which will allow for expansions and contractions.
(d) Protection against decay and termites.
Wood used in the construction of the collector or mounting, and exposed to outdoor conditions shall be pressure-treated with preservative or shall be a naturally durable, decay resistant species of lumber and shall be protected against termites.
(e) Protection from heated components.
Components which are maintained at temperatures above 170°
F shall be protected from human contact. The protections may be in the form of insulation, metal or plastic guards.
(5) Smoke detectors.
All dwellings that contain air systems with wood-frame collectors shall be provided with smoke detectors as specified in s. SPS 321.09
(6) Fire protection.
The design and installation of the solar energy system and components shall provide a level of fire safety consistent with chs. SPS 320
for one- and 2-family dwellings, or chs. SPS 361
for commercial buildings.
SPS 371.21(6)(a)1.1. `Existing buildings.'
An existing building's vents, pipes, and ducts, installed for the operation of the solar energy system, shall comply with chs. SPS 361
2. `Existing dwellings.'
Existing dwellings shall be provided with draftstopping at openings around vents, pipes and ducts installed for the operation of the solar energy system. Draftstopping materials may not be less than 1
-inch gypsumboard, 3
-inch plywood, mineral-based insulation or other approved materials.
A collector intended for installation integral with or forming a part of the building or dwelling roof structure and its associated roof covering material, may not reduce or impair the fire resistance of the designated roof covering material.
The structural design of the solar energy system, including connections and supporting structural elements, shall be based on loads anticipated during the design life of the solar energy system. Roof loading due to the following loading effects shall be included in the design of all structural elements influenced by these loads:
SPS 371.21(7)(a)1.1. `Collector.'
The collector and supporting structure, including building components, shall be designed and constructed to support the weight of the collector, other components and heat transfer fluids.
2. `Thermal storage.'
The thermal storage and supporting structure shall be designed and constructed to support the weight of the storage container, components, heat transfer fluids and storage medium.
SPS 371.21(7)(b)1.1. `Use.'
Surfaces that must support maintenance personnel shall resist a load of 250 pounds distributed over a 4-inch square area.
2. `Wind, snow and seismic.'
The collector, including any mounting hardware and building components, shall be designed and constructed to resist the wind and snow loads specified in chs. SPS 320
for one- and 2-family dwellings, or the wind, snow and seismic loads specified in chs. SPS 361
for commercial buildings.
SPS 371.21 History
Cr. Register, June, 1986, No. 366
, eff. 7-1-86; CR 01-139
: am. (2), (5), (6) (intro.), r. and recr. (7) (b) 2., r. (7) (b) 3. Register June 2002 No. 558
, eff. 7-1-02; correction in (6) (a) 1. made under s. 13.93 (2m) (b) 7., Stats., Register June 2002 No. 558
; correction in (1) (c) 2., (2), (5), (6) (intro.), (a) 1., (7) (b) 2. made under s. 13.92 (4) (b) 7., Stats., Register December 2011 No. 672
SPS 371.22 General mechanical requirements. SPS 371.22(1)(1)
When a solar energy system and an auxiliary energy system are interconnected, the design temperature or design pressure of either system may not be exceeded. The interconnection may not compromise or bypass any required safety devices on either system. Auxiliary equipment shall be compatible with the solar energy system output, including but not limited to, temperatures, pressures and heat transfer fluid type.
(2) Identification of materials.
Components and materials used in solar energy systems shall be permanently marked or labeled by the manufacturer as to the component's limitations. All listed components shall have the seal of the listing agency permanently affixed to the component.
All components of the solar energy system having valves capable of isolating heat generating or heat transfer components shall be provided with an approved, adequately sized pressure relief valve. The installation of the relief valve discharge shall be in accordance with s. SPS 382.40 (5)
The pressure relief valve shall be set at a pressure not to exceed the design pressure of the solar energy system or component or 150 psig, whichever is lesser. The relief valve settings may not exceed the recommendations of the valve manufacturer.
Temperature relief valves shall be of adequate relief rating expressed in Btu/hr for the components served.
Temperature relief valves shall be installed in thermal storage so that the temperature sensing element is immersed within the top 6 inches of a storage tank that contains liquid. The temperature relief valve shall be set to open at 210°
F or less.
(d) Combination pressure-temperature relief valves.
Combination pressure-temperature relief valves shall comply with all the requirements of the separate pressure and temperature relief valves.